Implantable cuff with an integral closure mechanism

ABSTRACT

An integral closure mechanism is described to be used for implantable cuffs of tubular shapes. This mechanism relates to cuffs used to surround internal organ or tissue in animals and human for specific clinical applications or for evaluation purposes in biomedical research. The closure mechanism is designed to provide a safe and reliable way in keeping the cuff in its original dimension around biological tissue, and to assist in surgical implantation by introducing a convenient and less time consuming method to secure the cuff at the surgical site. To eliminate distortion of the implantable cuff by having an integral closure mechanism, the underlying body tissue is better protected from damages caused by compression of the cuff and from connective tissue overgrowing at the distorted sites. Thus, therapeutic attempts by using implantable cuffs may reach their desired potential in various applications.

FIELD OF THE INVENTION

This mechanism is designed for implantable cuffs used in both fields ofresearch and clinical settings. The intended applications of cuffs orthe particular study of interest do not relate to this mechanism.Biomedical research, animal studies, clinical applications fortreatments at the hospital, or localized pharmacological approach arepotential fields to receive benefits of using implantable cuffs withthis mechanism. This closure mechanism is incorporated to be part of theimplantable cuff to give a better seal along the edges of the cuff, andto stabilize cuffs with locking units to avoid unwanted re-opening ofcuffs during implantation and after completion of the surgicalprocedure.

BACKGROUND OF THE INVENTION

Several implantable cuffs have been used in research and very few areused in clinical settings for treatments. Prior cuffs were designed toenclose the tissue and to close with sutures. There are disadvantagesfrom the use of sutures to close the cuff. For instance, suture materialeither absorbable or non-absorbable can retain contaminants or serve asa focal point for connective tissue to grow around it. Sutures used forimplantation has a lifetime of a few months inside human body to providea constant tensile strength. Sutures may be required to close the cuffsfor an extended period of time to prevent re-opening of the cuffs forthe clinical applications. Another disadvantage is when sutures do notclose the cuff tightly, connective tissue may grow inside the cuff andthis interferes with the interaction at the interface between the cuffand the enclosed tissue. When sutures close the cuff too tightly, it maylead to inflammation at the enclosed site and increase the chance ofcuff implant failure. Furthermore, if sutures can not stabilize thedimension of the cuff, the edges of the cuff may overlap each otherresulting in tissue damages inside the cuff.

The above disadvantages associated with prior cuff design can beaddressed with the closure mechanism in this patent. This closuremechanism can provide a stable dimension for the cuff, and to ensure asmooth continuous outer surface to prevent tissue growing inwardly tothe cuff lumen and to eliminate potential focal points created by usingsutures. The cuff membrane and its closure mechanism are made ofbiocompatible and durable materials that can last minimum of 10 yearsinside human body without significant defect. Although to increasenumber of closing sutures may improve the efficacy of the implantablecuff, it also increases the opportunities of having tissue growth,contaminations and complications. This is a potential disadvantage ofusing cuffs in the clinical settings. Decreasing the number of closingsutures may save time and simplify the procedure of implantation, but itincreases the chance of cuff opening as sutures break down, andcomplications or failures associated with cuff opening. Reliable suturesused for implantations are relatively inexpensive to obtain and verycost effective for the end users. However, the cost of removing cuffs,procedure failures, risk of sutures break down, complications, recovery,re-evaluation and re-implantation are fairly expensive to the healthcare system, insurance companies and end users. The described closuremechanism in this patent is easy to use, non-technique sensitive, notrequired of specialized skills, and time saving compared to usingsutures.

It has been difficult to use cuffs for implantation. It requiresspecialized tools and surgical procedures may be challenging. To implantaround a nerve or tissue of particular locations may also be risky usinga cuff. Many clinicians are reluctant to use cuffs for implantationprocedures. It is delicate, time consuming, and skills required to cleanout surrounding tissue and to isolate the tissue of interest. There isno simple method to open and orient the cuff during implantationprocedures. The body tissue may be compressed or damaged when the cuffis not closed properly or when the surrounding tissue is not cleanedwell enough. In case of complication or failures, to remove implantedcuff can be difficult due to connective tissue growth and limitedaccess.

SUMMARY OF THE INVENTION

The cuff having a closure mechanism in this patent can improve thesurgical procedure for cuff implantation. This cuff and the integralclosure mechanism are shown in FIG. 1. The cuff can be opened withfingers and passed around the tissue with ease. After property enclosingthe body tissue, the cuff can be closed and locked with finger pressure.When the cuff is closed, the closure mechanism seals the edges of thecuff. When the tissue of interest is not properly oriented forimplantation or the surrounding tissue is not retracted well at thesurgical site, the cuff will not close. Since the outer surface of thecuff is smooth and continuous when closed, the potential problem oftissue growth is minimized. When implanted cuffs are indicated forremoval, the removing procedure is not complicated. The closuremechanism can be released and closed by using fingers. No specializedtools are needed to open and orient the cuff during implantation. Aretractor is illustrated in FIG. 8 to assist in retracting soft tissueduring surgical procedures. It has a design to enhance the visualizationat the surgical site and protect surrounding tissue from being damaged.This patent holds the design to reduce chances of cuff implantassociated complications and failure.

BRIEF DESCRIPTION OF DRAWINGS

The following drawings depict general embodiments of the implantablecuff and its closure mechanism.

FIG. 1 is a diagrammatic view of the implantable cuff in a closed andlocked position. The implantable cuff is constructed with abiocompatible and durable material. Its outer and inner surfaces aresmooth without flaps, gaps or overlapping.

FIG. 2 illustrates two parts of an implantable cuff. A tubular cuffmembrane has a near circumferential shape and a longitudinal hinge. Theother part is the relatively rigid closure mechanism with built-inlocking units.

FIG. 3 shows the cross section through a plane of the cuff in FIG. 1.From this view, both closure mechanism and locking units are shown atclosed and opened positions.

FIG. 4 is the implantable cuff at a slightly opened position. Thisdiagram of the cuff is when the closure mechanism is just beingreleased. The cuff is passive at this opening position without anyinternal or external forces exerting from or caused by its material andcomponents. In this view, a pair of closing components A and B can beseen separately at both ends of the cuff membrane along the longitudinaledges. Within A and B, there are a set of three to five locking units Cembedded in them.

FIG. 5 illustrates specific points on the implantable cuff to aid inreleasing closure mechanism, opening up the cuff to enclose body tissue,and closing the cuff. FIG. 5A and FIG. 5C show specific points toutilize for this purpose. Holding Points and Pressing Points are locatedon the cuff membrane along the longitudinal border of the closuremechanism. Holding Points are near the closing component B where the endof the hook shape pattern constitutes the outer surface of the cuff.Pressing Points are near the closing component A where the end of thehook shape pattern constitutes the inner surface of the cuff. FIG. 5Band FIG. 5C show the cuff opened by rotating perpendicular to the axialplane of the hinge. The hinge of the cuff membrane is indicated by Uwhich runs parallel to and on the opposite side of the closuremechanism. The function of the hinge is to enable the cuff to openfurther and to create access to enclose specific body tissue withoutdisturbing the dimension of the cuff.

FIG. 6 shows the implantable cuff membrane encloses a nerve wheremultiple fascicles can be seen from the cross section of the nerve inFIG. 6A. FIG. 6B is a diagram of a nerve enclosed by the cuff with theclosure mechanism. The nerve is surrounded by the cuff, but the enclosednerve is not being affixed nor tightens. The cuff is not movable norloosens along the enclosed tissue.

FIG. 7 is a diagrammatic view of the semi-flexible hinge. The hinge ismade of biocompatible rigid and flexible materials alternating with eachother forming a string of semi-flexible hinge. The hinge has attachmentsites located along its longitudinal axis. The sites of attachment onthe hinge determine the degree of rotation around its perpendicularplane or axis of rotation.

FIG. 8 illustrates the design of a retractor. It is designed as a nerveor vein retractor, and it can also be used for soft tissuerepositioning. It has a handle that fits in between the thumb and theindex finger. The index finger of the user rests on the indentation atthe top surface of the instrument, and the side of the middle fingerrests at the bottom surface of the instrument. The top view of theretracting end is flat and the side view of the retracting end isslightly curved. This retractor handle has a passive grip design for theusers, and the retractor end can adapt various ends for otherapplications.

DETAILED DESCRIPTION OF THE INVENTION

Implantable cuff is used for surgical interventions in human andexperimental studies in animals. This patent describes an implantablecuff with a closure mechanism. The closure mechanism provides a safe andefficient way to join ends of the cuff membrane securely together. Thisimplantable cuff has several components and is fabricated as one singleunit. The cuff can not be dissemble, reassemble nor repaired. Avariation of this cuff is, instead of one single unit, having severalunits joining together by more than one closure mechanisms.

The cuff is comprised of a tubular cuff membrane, a pair of closingcomponents along the longitudinal ends of the membrane, a semi-flexiblehinge, and a set of locking units built-in to the pair of closingcomponents. Once the cuff is closed, the pair of closing componentscomes interdigitated to close the edges and the set of locking unitsfurther stabilize the closure mechanism. There is neither overlappingnor gaps on the outer surface of the cuff, and the cuff is sealed alongthe edge when closed.

In reference to FIG. 1, the diagrammatic design of the implantable cuffis in an ideal closed and locked position. The cuff is fabricated as onesingle unit. The tubular part of the cuff as illustrated in FIG. 2 ismade of biocompatible materials with flexible or rigid physicalproperties that are suitable for housing components of specificapplications. FIG. 2 shows a semi-flexible hinge that is embedded withinthe tubular cuff membrane and is parallel to the two longitudinal edgesof the cuff. The closure mechanism as shown separately from the cuffmembrane in FIG. 2 is constructed with a relatively rigid and durablematerial. FIG. 3 shows cross sectional views of the implantable cuff atits opened and closed positions. At its closed position, the implantablecuff has a near circular shape. The semi-flexible hinge is used forfurther opening the cuff once the closure mechanism is released. Inreference to FIG. 4, the closure mechanism constitutes a pair of closingcomponents, and a set of built-in locking units along the two edges ofthe cuff. When the cuff is opened, two closing components can be seenalong the two longitudinal edges of the tubular cuff shown in FIG. 4.When the cuff is closed, the pair of closing components comesinterdigitated with each other to close and seal the cuff along theedge. The built-in locking units stabilize the cuff at the closedposition, and prevent the cuff to re-open due to unwanted movements orforces from surrounding or enclosed tissue and applications during andafter implantation.

The inner surface of the cuff membrane may equips with pouches, pads orsmall silicone protrusions as needed for installing clinicalapplications to deliver therapeutic agents such as drugs and chemicalsor electrical currents to the enclosed nerves, veins, muscles,intestines, and etc. The cuff can be used to support tissues or topromote wound healing. Electrodes can be embedded in the cuff to giveelectrical impulses to the surrounding tissue or to elicit certainphysiological responses for specific study of interest. Furthermore, thecuff could be modified in other variations to record physiologicalsignals.

The closed implantable cuff creates a lumen shown in FIG. 1 to encloseinternal body organ or tissue of tubular shape such as nerves, veins,muscles, intestines, and etc. The cuff sizes can be fabricated accordingto specific organ of interest and particular physiological responses tobe elicited. Clinical applications of the implantable cuff with thissafe and effective closure mechanism are to eliminate disadvantages ofusing sutures to close the cuff, to equip interfacing between internalbody tissue and therapeutic agents with a reliable delivery method,preventing failure due to complications, to provide a non-techniquesensitive approach and a time saving alternative for various surgicalprocedures.

The implantable cuff has Holding Points H and Pressing Points P to usefor opening and closing the cuff. H and P points are shown in FIG. 5Aand FIG. 5C. An instrument such as nerve or vein retractors can beuseful for making access and retracting body tissue once the surroundingconnective tissue is cleaned up and the body tissue is ready forenclosure. The never retractor shown in FIG. 8 has a passive griphandle, and a flat, slightly curved and non-cutting tip. Once the tissueis retracted or the access is made, the cuff can be passed through toenclose the tissue as it is shown in FIG. 6A. Holding H points andgently exerting pressure on P points rotate the cuff membrane and closethe cuff in a locked position as shown in FIG. 6B. It is not recommendedthat the cuff encloses the body tissue tightly nor should the cuff bemovable or loosen at the enclosure site.

Gently holding H points along the longitudinal border of the closuremechanism and exerting pressure onto the P points release the closuremechanism. The implantable cuff will open passively once the mechanismis released. Exerting additional pressure on P points further rotatecuff membrane perpendicular to the axial plane of the hinge, and openthe cuff wider to enclose body tissue. FIG. 5B and FIG. 5C illustratethe opening cuff. The hinge is indicated by U, and it runs parallel toand on the opposite side of the closure mechanism.

REFERENCES CITED U.S. Patent Documents

5,487,756 December 1994 Kallesoe et al. 6,461,368 B2 October 2002Fogarty et al.

1. An implantable cuff has the following component parts. (a) Alaminated tubular cuff membrane of a near circumferential shape hasadditional closing components extending along two edges of said cuffmembrane. These two longitudinal closing components A and B providehousings for a set of three to five locking units to further stabilizesaid cuff. When said implantable cuff is closed, it has acircumferential shape or a near circumferential shape viewing directlyfrom above the either end of said cuff. (b) Both said closing componentsA and B along the longitudinal edges of said cuff have zigzag profiles.From the cross sectional view, the far end of the profile has the shapeof a hook without a pointed tip. (c) The inner surface of said tubularcuff may be a relatively smooth surface of silicone or may containpouches, pads or small silicone protrusions for housing variousmechanisms according to specific therapeutic applications or clinicalevaluations, and to be prepared for additional molding process ofvarious applications. (d) Each locking unit contains a ball shapesilicone in the closing component B, and the corresponding recipienthousing is located in the other closing component A. Said ball shapesilicone of said locking unit can be round or parabolic in shapes butnot limited to. (e) A longitudinal semi-flexible hinge runs parallel tosaid closing components from one end of said tubular cuff to the otherend. When said cuff is closed, said hinge is at the opposite side ofsaid closure mechanism. The method to combine rigid and flexiblebiocompatible materials in any shape and size in an alternating manneris to fabricate said semi-flexible hinge and add degrees of rotation tothe application. A variation of said hinge is having attachment sitesand extending arms built on said semi-flexible hinge.
 2. The implantablecuff according to claim 1, wherein said laminated tubular cuff membraneis made of biocompatible and durable materials, and it can be rigid,flexible or a combination of both properties.
 3. The implantable cuffaccording to claim 1, wherein said semi-flexible hinge is made ofbiocompatible and durable materials. It is constructed by alternatingrigid and flexible rectangles made of said biocompatible and durablematerials joining end to end.
 4. The implantable cuff according to claim1, wherein said biocompatible materials of said cuff and said componentscan be made of but not limited to silicones.
 5. The semi-flexible hingeaccording to claim 1, wherein said range of rotation is perpendicular tothe axial plane of said hinge, and said range is determined by thepercentages of rigid and flexible rectangles used in said combinationsand their sizes and shapes in the construction.
 6. The semi-flexiblehinge according to claim 1, wherein said hinge has various attachmentsites along the longitudinal axis of said hinge, and said attachmentsites can be utilized to create different axial planes around said hingeby having extending arms connected to said hinge at said attachmentsites.
 7. The semi-flexible hinge according to claim 1, wherein saidhinge and said extending arms can be utilized to create a threedimensional object using two dimensional spaces.
 8. The semi-flexiblehinge according to claim 1, wherein said hinge is made of biocompatibleand durable materials when said hinge and variations are intended foruse in biomedical fields. The materials used can be made of siliconesbut not limited to. Materials used for said hinge and variations areused for but not limited to the biomedical fields.
 9. The semi-flexiblehinge according to claim 1, wherein said variation of said hinge havingattachment sites and extending arms can be used to create supportingframes in various applications, and said materials can be adjusted forsaid hinge and variations to be used for other purposes in variousindustries.
 10. The implantable cuff according to claim 1, wherein saidclosing components of said cuff is made of biocompatible and durablematerials. The materials can be made of silicones but not limited to.Said closing components, said cuff membrane, and said hinge are joiningtogether by molding or gluing, but not limited to.
 11. The implantablecuff according to claim 1, wherein said closing components of said cuffare fitted interdigitated together to close and seal the cuff
 12. Theimplantable cuff according to claim 1, wherein said locking units ismade of biocompatible and durable materials. The materials can besilicones but not limited to. Each said locking unit is embedded in theclosing components.
 13. The implantable cuff according to claim 1,wherein said locking component of said cuff is consisted of minimum of 3locking units to stabilize said cuff
 14. The implantable cuff accordingto claim 1, wherein said cuff has a smooth and continuous outer surfacewhen it is closed.
 15. The implantable cuff according to claim 1,wherein said cuff membrane has a smooth inner surface and interrupted byspecific applications made of biocompatible materials such as metalelectrodes, but not limited to.
 16. The implantable cuff according toclaim 1, wherein said cuff is one single unit but not limited to. Avariation of said cuff could be more than one units joining together byclosure mechanisms. All parts and segments can not be dissembled,resembled or repaired.
 17. The implantable cuff according to claim 1,wherein said cuff could be modified in other variations to be used forrecording physiological signals from the enclosed tissue.